1. Field of the Invention
This invention relates to heat exchangers, and more particularly, to techniques for handling and erecting pendant superheaters of a steam generating system.
2. Description of the Prior Art
In the construction of steam generating systems, such as the commonly known power stations of the electrical utilities, the handling and erection of bulky and heavy steam generating components is both difficult and costly. One such component, the pendant superheater, is a heat exchanger suspended from supports at the upper portion of a steam generator generally consisting of a plurality of long interconnected tubular elements connected to a header. These tubular elements are commonly assembled in a plurality of spaced panel arrangements, called platens, oriented in a plane perpendicular to the longitudinal center line of the header and extending along the length of the header which may be as large as 50 feet or more. Obviously, it is extremely difficult, and excessively costly to erect one complete pendant superheater up to its above ground operating position. However, it is also desirable to fabricate as much of the superheater as is practical to erect, and thereby reduce expenses, for example, incurred in erecting rigging and performing a substantial amount of superheater welding in an above ground on location condition.
Heretofore, it has been the practice in the shipment, handling and erection of steam generator components, such as pendant superheaters, to package and support a segment or section of a superheater header and accompanying tubes in a heavy timber or metal framework. Moreover, it is essential that provision be made for lifting this segment of the superheater, including the framework, as by a crane hoist, in order to place the superheater segment on and remove it from a freight car or other transport vehicle, as well as to erect the superheater segment into its operating position. However, the cost of such framework for each superheater and the cost to return an empty frame back to the construction plant to fit another superheater segment thereto for shipment or for storage may be economically impractical. Furthermore, each such frame structure must be specially constructed to accommodate each superheater segment, and because weight is a determining factor in the size of the component to be erected, the heavy framework may reduce the size of the component or segment to be lifted.
Accordingly, there is a need to provide industry with a more economical structure which is adaptable to the handling and erection of many steam generator components, such as pendant superheaters.